Enhancement of magnetic relaxation properties with 3d diamagnetic cations in [ZnLn] and [NiLn], Ln = Kramers lanthanides

• Published in: Dalton transactions : an international journal of inorganic chemistry 2019-01, Vol.48 (2), p.641-652
• Main Authors: Mayans, Júlia, Saez, Queralt, Font-Bardia, Mercè, Escuer, Albert
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c8dt03679a

Employing the chiral bi-compartmental Schiff-base ligand H 2 L obtained from the condensation of ( RR ) or ( SS )-1,2-diphenyl-ethylenediamine and o -vanillin, we report the structural characterization of the discrete dinuclear pairs of enantiomers [Ni II Eu III ] 1 RR , 1 SS and [Zn II Eu III ] 2 RR , 2 SS and the magnetic properties for the series of complexes [Ni II Ln III ], Ln = Ce, 3 RR ; Nd, 4 RR ; Dy, 5 RR ; Er, 6 RR , Yb, 7 SS and [Zn II Ln III ], Ln = Ce, 8 RR ; Nd, 9 RR ; Dy, 10 SS ; Er, 11 SS and Yb, 12 RR in which M II is diamagnetic and Ln III is a Kramers lanthanide. Single crystal X-ray diffraction shows that relevant changes in the [Zn II Ln III ] structures are produced after a period in open air ( 2 RR b , 2 RR c ), evidencing that the lability of the ligands bonded to Zn II can modify the structures that will be correlated to the experimental measurements. The dynamic magnetic measurements showed that the [Ni II Ln III ] and [Zn II Ln III ] derivatives exhibit different behaviors in the relaxation of magnetization especially for oblate and prolate Ln III cations. Comparison between two series of [Ni II Ln III ] and [Zn II Ln III ] dimers reveals lower intermolecular interactions for the square-planar Ni II derivatives that favour an induced SIM response. Some unusual Ce III , Nd III and Yb III SIMs are reported.